1. Field of the Invention
The present invention relates generally to a covering element for the interior of a motor vehicle.
2. Description tf the Related Art
More precisely, the invention relates to a covering element for the interior of a motor vehicle of the type having a visible face and an invisible face opposite the visible face, the covering element comprising a weakening line which is formed on the invisible face and defines a gate zone which is to open under the pressure of the deployment of an airbag when the motor vehicle is subjected to an impact, the weakening line comprising a groove which has a given total length and is delimited by a bottom and at least one transverse rib projecting relative to the bottom and closing the groove at least partially, the covering element having a thickness of material between the visible face and the bottom which is between predetermined minimum and maximum limits over most of the total length of the groove.
Such a covering element is known from JP-2006-315115, which describes that the groove is divided into a plurality of segments of identical length by ribs which are disposed at regular intervals along said groove.
Such a covering element does not comply with the demand made by motor vehicle constructors that the weakening line must remain invisible to the passengers in the vehicle despite ageing of the covering element, due especially to exposure to the sun, and also despite the subsequent steps of production of the covering element, such as, for example, the fixing of the covering element to the structure of the motor vehicle and/or the assembly of additional elements to the covering element by vibration welding, especially the duct which connects the airbag module and the covering element.
Nor does the covering element of the Japanese document meet the demand that the gate zone must permit satisfactory deployment of the airbag at low temperatures, typically at −30° C.